Failure to evaluate relevant visual information completely can lead to adverse consequences. In many cases, such as with medical imaging, no general methods exist that allow computer systems to detect abnormalities reliably, so human viewing is the usually the best available method for reliably detecting abnormalities. Detection of abnormalities and interpretation of the information relies on the human user's ability to detect and analyze abnormalities.
If the user does not view something, then it is not possible for him to detect and analyze it. For example, a doctor who never views a portion of a medical imaging exam cannot detect abnormalities within the unviewed portion. This can result in significant medical errors, such as missed cancers. A security screener who fails to view all the information on the screen of an x-ray baggage scanning device cannot detect the image of a gun passing through the machine.
Typically, a viewer of an image must rely on his or her own internal sense of having adequately viewed the image. This invention relates to a system that monitors a viewer as he views an image and provides feedback as to whether he has completely viewed the image. There are currently no systems that ensure that the user has adequately viewed all the relevant visual information presented.
Visual acuity varies across the visual field, with a small, roughly circular region of high resolution vision centrally (foveal or central vision) and lower resolution vision peripherally (peripheral vision). This variation in visual acuity is the result of a variation in the density and type of visual receptors within the retina at the back of the eye.
High resolution central vision or foveal vision is accomplished by a small region in the retina, the fovea, which contains densely packed visual receptors. This region represents the center of visual attention and also contains visual receptors responsible for color vision and daytime vision. The fovea provides sharp central vision needed for reading, examining medical imaging exams, and other activities were visual detail is important.
Because central vision is only a small part of the visual field, a viewer must scan an image to adequately view it in its entirety, rapidly moving from one site of visual fixation to the next through a series of visual saccades. If a viewer fails to view the portion an image containing a critical feature using his foveal vision for a sufficient duration, that critical feature, such as a cancer in a medial imaging exam, may be missed by the viewer.
Existing systems do not provide a means to verify that all critical portions of an image were viewed by central vision. Existing systems do not provide a means for indicating that an image was viewed with foveal-vision for a sufficiently long period to have been adequately viewed by the user.
Advances in medical imaging equipment, such as computed tomography (CT) and magnetic resonance imaging (MRI) have resulted in a tremendous increase in the number of images acquired for each imaging exam, commonly approaching and sometimes exceeding 1,000 images per exam. In addition, the number of imaging exams performed each year is growing. In addition, there is a shortage of radiologists, physicians who specialize in the interpretation of medical imaging exams.
The radiology field recognizes a data overload problem, where radiologists can become overloaded by too much data, too many images, and too many exams. Important diagnoses may be missed, as subtle, but important, imaging findings can be buried within very large imaging exams. These issues increase the need for inventions such as this.
In the past, medical images were traditionally recorded and viewed on x-ray film. Over the past decade, medical imaging has moved into the digital realm, where images are managed and viewed using computer systems known as picture archive and communication systems (PACS). While PACS systems have made the viewing of these large exams more practical, they have not eliminated medical errors related to misinterpretation of imaging exams. In fact, PACS systems allow radiologists to navigate through these large imaging datasets at speeds that can exceed their ability to detect all abnormalities. In the context of medical imaging, the goal of this invention is to reduce medical errors related to interpretation of medical images by monitoring the thoroughness with which the viewer has examined a medical imaging exam.
Knowing that an image is adequately viewed, and therefore, knowing that the image could be consciously considered by the viewer, would be highly beneficial to reducing errors in many tasks requiring visual perception, including those outside of medical imaging.